I have a Sig Kilo Rangefinder and you can easily see the IR laser while ranging looking through the PVS-14. I just hold the rangefinder on one eye and the PVS-14 on the other eye. The display on the Sig Kilo auto adjust the display brightness which helps in low light.
Small flex led light wrap some white cloth over led to diffuse it then the electrical tape to diameter necessary to fit into front. This will only work if the laser has its own lenses and the viewfinder looks straight thru. I have one setup for my range finder this way.
Like this style range finder
Black tape will hide any light from critters and you will see yardage nice and bright.